Locales fix

What does this MR do?

This adds the time_ago_in_words keys to the german locale file and adds some comments to explain the sections.

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed?

To get the german translation to work :)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

@rdavila Please review :)
I'll add the Changelog entry this afternoon after i get home.